Strapping machines are known for securing straps around loads. In one arrangement, during the strapping cycle, strap material is fed from a dispenser into a strapping machine. The strap is fed through a slack box, through a feed head and sealing head and into a strap chute. The strap is conveyed through the strap chute and back to the sealing head.
Once the strap returns to the sealing head, the lead end is gripped in a gripper, and the strap is pulled from the strap chute onto the load in a take-up portion of the cycle. The strap is then tensioned, in a tension portion of the cycle, and overlapping course of strap material are sealed to one another, as by welding, to form the strap joint. The strap is then severed downstream of the strap joint and the load removed hum the strapping machine. A subsequent lead end is then ready to be pushed through the strap chute to strap the next load.
In the take-up and tension portions of the cycle, the strap that is taken up or retracted from the strap chute must be stored within the strapping machine—in the slack box. This serves a number of functions. First, it provides storage for the strap that is taken up from around the load. Given the size and weight of the strap reel, and the inertia produced when the reel rotates to dispense strap, it would be impractical to rewind the taken-up strap onto the reel. The slack box thus provides a location to store this taken-up strap.
The slack box also provides for a quantity of strap material to be used for a subsequent strapping cycle, whether it is for a subsequent load or for an additional band around an already strapped load. Again, due to the force required to commence rotation of the reel, the inertia produced, and the slow start to rotation of the reel, the slack box provides a quantity of strap that can be fed on-demand, almost instantaneously, without having to bring the rotating reel up to speed in a short period of time.
However, with this arrangement, there must still be a physical path from the feed to the slack box (from the infeed to the slack box) to the outlet of the slack box (to the feed head), for example when initially feeding strap or after a misfeed. The physical path must, however, be movable so that once the strap extends through the slack box (from the infeed to the outlet), the path can be moved out of the way to prevent interfering with slack strap that is fed into, and drawn from, the box.
Accordingly, there is a need for a device that provides a strap guide for automatic strap feed into the strapping machine, from the strap supply to the feed head. Desirably, such a guide moves or a portion is moved from the strap path to permit strap to fill into the slack box. More desirably still, such a guide or guide portion automatically moves out of the strap path, without the strap having to “push” the guide portion, once the strap extends from the inlet to the outlet or feed head to establish the strap path.